Hydraulic impact tool



Dec. 15, 1953 w, H CUNE, JR 2,662,505

HYDRAULIC IMPACT TOOL Filed June 1G, 1951 ze Q . .ATTORNEY of travel byupper and lower axially extending fins 26 and 21 of which the latterform a shoulder for the compression spring 28 having its upper endengaging shoulder 29 on the hammer whereby the hammer is constantlyurged upwardly. Upward movement of the hammer under influence of thespring 28 moves the ball 30 into engagement with the seat 3I at thelower end of the valve sleeve I1 and hence normally holds the valve inengagement with its seat and the valve mechanism in its uppermostposition when the tool is not in operation.

By way of further description of the invention and explanation of theoperation of the disclosed embodiment, it will be assumed that the partsare in the relative positions shown in Fig. l of the drawings. The drillstem 2, the tool I and the bit 3 will be rotated in the usual manner.During such rotation, flushing uid is pumped downwardly through thedrill stem 2 where it exerts a pressure upon the upper end of the pistonI2 and the ball valve 30, whereby the piston I2, the valve sleeve I1,the ball 30 and the hammer 25 will be accelerated downwardly. When thepiston I2 engages stops I4 travel of the piston is terminated but thecontinuing flow of fluid to and through the passage I3 in the pistonwill cause the valve sleeve to travel until the rib I9 on the sleeveengages the fiange I8 in the housing 4 whereupon travel of the sleeve isterminated. During the continued travel of the sleeve, energytransmitted by the pumped fluid continues to accelerate the hammer 25.

It is to be noted that the fluid pressure initiating the downwardmovement of the hammer is applied throughout an area equal to that of acircle having the outer diameter of the piston I2. Thus the energy ofthe pressure fluid is eiliciently used to accelerate the hammer 25 whichis further accelerated by the fluid entering the passage I3 after thepiston has engaged the stop I4. This action continues until the rib I9on the valve sleeve II engages the flange I8 in the housing 4 at whichtime the hammer has attained its maximum velocity.

At the instant the rib I9 of the valve sleeve Il engages the ange I8 theball valve 30 moves from its seat 3l and the fluid then flowsunobstructedly about the hammer, through the passage 20 in the drivebushing and thence through the fluid passages in the bit 3 to rise-aboutthe tool and drill stem as already explained.

It is apparent that there is a drop in fluid pressure as the fluidpasses downwardly to and through the bit 3. Hence, the fluid pressurewithin the tool is greater than the pressure on its exterior, acondition of importance in the operation of the tool.

When the ball 30 leaves its seat, as illustrated in Fig. 7, the valvesleeve I1 moves upwardly until it engages the nether side of the pistonI2. rIhis movement is brought about by the pressure within the tool uponan annular area of the sleeve having a cross section indicated as Ai.Such pressure is opposed by a pressure in the chamber 22 upon a likearea on the upper end of the sleeve indicated as A2. Since the pressurewithin the tool is greater than that on its exterior as alreadyexplained, the differential pressure in an upward direction causes thevalve sleeve to move upwardly. At the same time the hammer 25 continuesits downward travel and engages the shank or anvil I0 on the drivebushing to impart energy by impact to the bit to supplement cutting`action thereby.

The hammer then moves upwardly and the ball 30 is again brought intoengagement with its seat 3| on the valve sleeve Il. Pressure againbuilds up above the piston I2 and the ball 30 and such pressuredecelerates the upward movement of the hammer. The valve sleeve I1 andthe piston I2 move upwardly with the hammer until its velocity isreduced to zero whereupon the succeeding stroke is initiated.

Not only does the invention, described by reference to the embodimentshown in the drawings. obviate the use of springs to obtain desiredvalving action but the structure is also such that pressure fluid isapplied to a piston of large cross section at those instants when aforce of high magnitude is Anecessary to produce high ac- Celeration ofthe hammer at the beginning of its downward stroke and to produce highdeceleration of the hammer as it approaches the end of its upwardstroke.

The invention provides an impact tool capable of attaining the objectsabove set forth and also a tool havingr high operating eiliciency with aminimum of maintenance. While the description is directed to a specificembodiment it is understood that the construction and combination of thesalient features of the invention may be altered without departing fromthe spirit of the invention.

The invention claimed is:

l. In a fluid actuated impact tool the combination comprising, a housinghaving a passage therethrough, there being spaced inlet and outlet forthe admission and exhaust of actuating fluid to and from the housing, areciprocable hammer within the housing intermediate the inlet andoutlet, means for moving the hammer upwardly after an impact has beenexerted thereby, a valve sleeve slidable axially of the housing and insealing engagement therewith, said sleeve being engageable with thehammer to close the passage through the sleeve so that fluid pumped intothe housing above the sleeve forces the sleeve and hammer downwardly,means for terminating the downward movement of the sleeve, whereby theseal between the sleeve and hammer is broken, means including an annularpiston having a portion fitting telescopically within the sleeve so thatthe upper surface of the sleeve is isolated from fluid pressure appliedto the interior of the sleeve, and additional means for subjecting saidupper surface to the fluid pressure exteriorly of the housing so thatthe valve sleeve moves upwardly under dilerential pressures exertedthereon after said seal is broken.

2. In a iiuid actuated impact tool the combination comprising, a housinghaving a passage therethrough, there being spaced inlet and outlet forthe admission and exhaust of actuating fluid to and from the housing, areciprocable hammer within the housing intermediate the inlet andoutlet, means for moving the hammer upwardly after an impact has beenexerted thereby, an annular piston mounted for reciprocation in thehousing above the hammer, stop means in the housing for limiting themovement of said piston, within the housing, a valve sleevetelescopically surrounding said piston and adapted to engage and form aseal with the hammer, Whereby the piston, sleeve and hammer move as aunit under pressure of fluid entering the housing above the piston,means for terminating downward movement of said sleeve afterpredetermined downward movement thereof relative to the piston, andmeans for thereafter hydraulically lifting the sleeve relative to thepiston.

3. In a iluid actuated impact tool the combination comprising, a housinghaving a passage therethrough, there being spaced inlet and outlet forthe admission and exhaust of actuating iluid to and from the housing, areciprocable hammer within the housing intermediate the inlet andoutlet, means for moving the hammer upwardly after an impact has beenexerted thereby, an annular piston mounted for reciprocation in thehousing, a valve sleeve slidably and sealably surrounding said pistonand engageable with the hammer to close the passage through the housing,and a seal between said sleeve and the housing below the piston, therebeing a passage between the interior and exterior of the housing abovesaid seal whereby the sleeve is subjected to the differential pressurebetween the interior and exterior of the housing and moves to an upwardposition when the hammer moves from engagement with the sleeve.

4. In a fluid actuated impact tool, a tubular housing having spacedinlet and outlet for the admission and exhaust of the actuating uid toand from the housing, an inwardly extending flange in the housing andspaced from the upper end thereof to form upper and lower chambers inthe housing a valve sleeve slidable within said ange, an annular pistonreciprocable in the upper chamber and having telescopic relation withsaid sleeve, whereby an annular chamber is formed about said sleeve,there being a port in the housing between said annular chamber and theexterior of the housing, a hammer reciprocably mounted in the lowerchamber, and means normally urging said hammer in an upward direction toengage and form a seal with said sleeve to close the passage through thetool.

5. In a fluid actuated impact tool, a tubular housing having spacedinlet and outlet for the admission and exhaust of the actuating iluid t0and from the housing, a valve assembly reciprocably mounted therein, andcomprising, an annular piston and a valve sleeve mounted for telescopicmovement, separate means for limiting the downward travel of the pistonand for thereafter terminating downward movement of the valve sleevewhereby the piston and sleeve are in extended position, a seal betweenthe sleeve and housing whereby an annular chamber is formed about thevalve assembly, there being a passage between said chamber and theexterior of the housing, a hammer reciprocably mounted in the housingbelow said valve assembly, a seat on said sleeve engageable by saidhammer to close the passage through the tool, and means normally urgingthe hammer in an upward direction to engage said seat.

WILLIAM H. CLINE, JR.

References Cited in the le of this patent UNITED STATES PATENTS NumberName Date 2,507,585 Bassinger May 16, 1950 2,584,979 Bassinger Feb. 12,1.952

